code: def _check_args(
      self, x1, x2, kernel, last_dim_is_batch=False, **params
  ):
      if not torch.is_tensor(x1):
          return "x1 must be a tensor. Got {}".format(
              x1.__class__.__name__
          )
      if not torch.is_tensor(x2):
          return "x1 must be a tensor. Got {}".format(
              x1.__class__.__name__
          )
  
imports: import functools
  from typing import Callable
  import torch
  from linear_operator import LinearOperator, to_linear_operator
  from linear_operator.utils.getitem import _noop_index
  from ..None import beta_features, settings
  from ..utils import deprecation
  from ..utils.memoize import cached
label_desc: Use image node_id 1 for calling the LazyEvaluatedKernelTensor obj's underlying member method code with example usage: obj._check_args(x1, x2, kernel, last_dim_is_batch) and returns: str, str